The increasing incidence of carbapenemase-producing Enterobacteriaceae (CPE) is a global health concern, as treatment options are extremely limited. The prevalence of CPE in UK hospitals is unknown, as national screening guidelines only recommend screening in patients considered to be at high-risk of CPE. Patients in intensive care units (ICU) are at high-risk of healthcare-associated infections caused by multidrug-resistant organisms (MDRO).
We conducted a six-month prospective surveillance study to determine the prevalence of MDRO in a UK teaching hospital ICU. Between June and December 2016, all adult patients admitted to ICU were screened for MDRO on admission, on discharge, and weekly during their ICU stay. Surveillance samples included stool or rectal swabs, urine, sputum or tracheal aspirates, and wound swabs (if wounds were present). Isolates were characterized phenotypically before undergoing whole-genome sequencing (WGS), epidemiological, and phylogenetic analyses.
During the first week of the study we identified stool carriage of a multidrug-resistant Klebsiella pneumoniae strain in two patients neither of whom had recognized risk factors for CPE. Both isolates were resistant to all antibiotics tested, apart from colistin, and were PCR-positive for the blaNDM-1 gene. Enhanced surveillance by the infection control team identified four additional patients in several wards who had stool carriage (n = 3) or bloodstream infection (n = 1) with a blaNDM-1K. pneumoniae isolate. Epidemiological links were identified between these six patients. Five months later, a second outbreak of multidrug-resistant K. pneumoniae was detected, involving stool carriage by four patients on two different wards. Environmental screening identified environmental contamination with multidrug-resistant K. pneumoniae on one ward. DNA sequence analysis confirmed that a novel blaNDM-1K. pneumoniaelineage (ST78) was responsible for both outbreaks in the hospital.
We identified two unsuspected blaNDM-1K. pneumoniae outbreaks in patients with no recognized risk factors for CPE. This highlights the importance of prospective surveillance for MDRO in high-risk settings, such as ICUs, and supports the use of rapid WGS to support outbreak investigations in real-time.
All authors: No reported disclosures.
No-touch disinfection systems like xenon- or mercury-based ultraviolet (UV) are now commonly being used for hospital room disinfection. However, serial exposure to UV light can potentially lead to the development of bacterial resistance. We sought to determine whether UV resistance develops due to serial exposure to UV light using 3 epidemiologically important multidrug-resistant microbial strains.
Methicillin-resistant Staphylococcus aureus (MRSA), carbapenemase–producing Klebsiella pneumoniae (KPC) and metallo-β-lactamase–producing Klebsiella pneumoniae (MBL) were serially exposed to 25 growth-irradiation cycles of UV produced by a xenon-based UV (Xe-UV) lamp for 5 minutes or a mercury-based UV (Hg-UV) lamp for 10 minutes. After each UV exposure cycle, the surviving colony-forming units (CFUs) were measured and compared with the initial inoculum of each cycle for each strain, respectively.
In each cycle, ˜1–10 million of MRSA, KPC, and MBL were used to test the effect of UV irradiation. Postexposure colony counts remained low (3–100 colonies) throughout the 25 serial exposures to both xenon- and mercury-based UV. The log-kill rate after each exposure showed no changes following UV disinfection by Xe-UV. The MRSA log-kill rate increased after repeated exposure to Hg-UV unlike KPC and MBL K. pneumoniae, which did not change. Whole-genome sequencing (WGS) analyses performed on these 3 strains demonstrated no significant genetic changes after multiple UV irradiation cycles.
Exposure of multidrug-resistant bacteria to UV produced from 2 different UV sources did not engender UV resistance after 25 serial exposures, as demonstrated by WGS analysis; thus, UV disinfection is unlikely to generate UV-resistant hospital flora.
The evolutionary epidemiology, resistome, virulome and mobilome of thirty-one multidrug resistant Klebsiella pneumoniae clinical isolates from the northern Vila Real region of Portugal were characterized using whole-genome sequencing and bioinformatic analysis. The genomic population structure was dominated by two main sequence types (STs): ST147 (n = 17; 54.8%) and ST15 (n = 6; 19.4%) comprising four distinct genomic clusters. Two main carbapenemase coding genes were detected (blaKPC-3 and blaOXA-48) along with additional extended-spectrum β-lactamase coding loci (blaCTX-M-15, blaSHV-12, blaSHV-27, and blaSHV-187). Moreover, whole genome sequencing enabled the identification of one Klebsiella variicola KPC-3 producer isolate previously misidentified as K. pneumoniae, which in addition to the blaKPC-3 carbapenemase gene, bore the chromosomal broad spectrum β-lactamase blaLEN-2 coding gene, oqxAB and fosA resistance loci. The blaKPC-3 genes were located in a Tn4401b transposon (K. variicolan = 1; K. pneumoniaen = 2) and Tn4401d isoform (K. pneumoniaen = 28). Overall, our work describes the first report of a blaKPC-3 producing K. variicola, as well as the detection of this species during infection control measures in surveillance cultures from infected patients. It also highlights the importance of additional control measures to overcome the clonal dissemination of carbapenemase producing clones.
AbstractObjectiveRecovery of multidrug-resistant (MDR) Pseudomonas aeruginosa and Klebsiella pneumoniae from a cluster of patients in the medical intensive care unit (MICU) prompted an epidemiologic investigation for a common exposure.MethodsClinical and microbiologic data from MICU patients were retrospectively reviewed, MICU bronchoscopes underwent culturing and borescopy, and bronchoscope reprocessing procedures were reviewed. Bronchoscope and clinical MDR isolates epidemiologically linked to the cluster underwent molecular typing using pulsed-field gel electrophoresis (PFGE) followed by whole-genome sequencing.ResultsOf the 33 case patients, 23 (70%) were exposed to a common bronchoscope (B1). Both MDR P. aeruginosa and K. pneumonia were recovered from the bronchoscope’s lumen, and borescopy revealed a luminal defect. Molecular testing demonstrated genetic relatedness among case patient and B1 isolates, providing strong evidence for horizontal bacterial transmission. MDR organism (MDRO) recovery in 19 patients was ultimately linked to B1 exposure, and 10 of 19 patients were classified as belonging to an MDRO pseudo-outbreak.ConclusionsSurveillance of bronchoscope-derived clinical culture data was important for early detection of this outbreak, and whole-genome sequencing was important for the confirmation of findings. Visualization of bronchoscope lumens to confirm integrity should be a critical component of device reprocessing.